1. Field of the Invention
The present invention relates to an underground storm shelter. More particularly it relates to modular storm cellar providing sanctuary to occupants during the deadly high winds encountered during tornados and hurricanes. The disclosed device is especially useful in providing emergency refuge to occupants of mobile homes or trailers which are especially susceptible to the high winds and high speed projectiles encountered during tornados. Dual access ports on preferred embodiments provide additional utility by providing both instant access during the short warning period prior to a tornado, as well as an emergency exit should the mobile home collapse on its piers and block the communicating trap door access once the storm has cleared.
2. Prior Art
Damage and loss of life in the United States from tornados and the winds associated with hurricanes is staggering. As an example, in 1987 there were 656 tornados in the United States resulting in the death of 59 citizens. In 1982, one of the worst years on record, there were 1046 tornados, causing an aggregate 64 deaths amongst the population of the United States living in constant fear of the deadly storms which occur in the Mid-West portion of the country. In an average year, no less than 850 tornados strike the Midwest. A major portion of theses deadly and damaging storms strike a stretch of the Midwest known as xe2x80x9cTornado Alleyxe2x80x9d which, due to geographic factors of the Rocky Mountains and atmospheric interaction of weather over the great plains, stretches from Texas to Wisconsin.
During a tornado and a xe2x80x9csuper cellxe2x80x9d thunderstorm surrounding the tornado for miles around, the winds and hail, and rain, become extremely dangerous to any human or animal life form unfortunate enough to be caught in the path of the storm. Tornados themselves can range from small weak storms with 40 mile an hour winds, to large frustro conic shaped whirlwinds contacting land in a xc2xd mile wide swatch. Winds at the contact point of a tornado with the ground can easily reach 300 miles per hour, and can last from a few seconds, to several hours, as the storm creates a path of destruction over an entire state.
When such a disaster approaches any populated area, people are typically instructed to seek safe haven from the approaching high winds, and the wind driven projectiles. Such winds and projectiles as large as automobiles or mobile homes can destroy a home and kill any person unlucky enough to encounter the path of destruction and terror that is a tornado. Equally devastating, but with more warning attached, are hurricanes that come into contact with coastal areas of the United States and can generate sustained high winds over 150 miles per hour for hours at a time.
Safe haven in such a terrifying event as a tornado or hurricane is generally a safe zone inside a permanent substantially reinforced structure, or optimally, a basement encased below the structure and below ground level. In the event that a basement is not available, a center section of the structure surrounded by as many walls, and as much of the structure itself is preferable to help stop the wind and more importantly the wind driven projectiles from injuring or killing the structure occupants. Projectiles can have the effect of a small ballistic missile when accelerated by high velocity storm winds.
In many historically tornado prone areas in the Midwest, storm cellars under the home or below ground adjacent to the home have been a common inclusion into housing for decades. In recent years, manufacture housing, which is factory built and moved to a pre-poured slab foundation, has caused a large portion of new permanent housing to be built without any underground shelters for the occupants. Also in recent years, the popularity of mobile homes and trailers have evolved to become a huge provider of housing to citizens of the Midwest. Such homes come in styles that appear as trailers to homes which look essentially like frame and brick structures.
The vast majority of mobile homes and trailers are typically parked on a small cement slab and secured on piers to maintain the mobile home in a level platform for long term use. Unfortunately, such a minimal securement to the ground, and the thin walls of mobile housing, combine to yield an extremely dangerous combination during tornados and hurricanes. Projectiles driven by high wind velocity can easily pierce one or even multiple walls of mobile housing becoming deadly to any occupants still inside.
Since most such mobile housing essentially rests on top of ground supported piers by the simple force of gravity, there is a propensity of mobile housing to be highly prone to roll over in high winds. It is not uncommon for mobile homes to be picked up by a tornado and deposited yards or miles away in a heap. Further wind driven trees, branches, boards, glass, and other projectiles piercing the walls of such housing render them virtually useless for protection against a tornado and in many cases the lower speed winds of a hurricane.
But because of the very nature of mobile housing being mobile, and having a floor and floor mounted interior structure that is supposed to be mobile, secure mounting, basements, and attached storm cellars, are almost always precluded from attachment to the mobile home or trailer. Consequently, a tornado approaching with normal little or no warning, can easily catch the occupants of the mobile home by surprise resulting in death or injury when the occupants have no storm shelter within easy access. There thus exists a need for an easily manufactured and installed shelter from the high winds and projectiles generated by tornados and hurricanes.
In recent years some prefabricated units have been designed and sold, but these are generally designed to be buried adjacent to, or under, a permanent structure style home. Usually such units provide a single access door which communicates between ground level and the cavity inside the unit. They require a significant investment in excavation and are prone to trapping occupants should the overhead structure collapse on the shelter.
The device as herein disclosed is a significant improvement in the provision of storm cellars in that it can be installed after the main structure has been built. It is modular in nature and can thus be initially constructed as a small shelter and later added onto to increase the size if needed. Further, the disclosed device provides a significant increase in the safety of occupants of mobile housing such as mobile homes and trailers because it can be installed adjacent to the poured concrete slab conventionally used for mounting of mobile housing. This is accomplished by providing an emergency trap door shoot for occupants of mobile housing to quickly enter the emergency shelter, as well as a second access port to provide outside access as well as an exit in the event that the trailer is turned over or collapses on the emergency entrance. A break away extension tube from the first access port provides communication to the interior of the shelter while affording protection to the occupants of the shelter in the event that the mobile home is sheared from its piers from the high winds.
U.S. Pat. No. 4,955,166 (Qualline) addresses the issue of an underground shelter that can be built and then buried. However, Qualline addresses, primarily, the issue of water proofing, lacks an emergency chute, and requires extensive excavation to mount.
U.S. Pat. No. 4,534,144 (Gustafsson) teaches an underground bomb shelter and storage unit, however, it provides no easy access to users and only one entry and exit port.
U.S. Pat. 5,749,181 (Bauman) teaches a trench mounted tubular emergency shelter, however, Bauman fails to offer an emergency access port required when users have only a moments notice of impending disaster and fails to teach dual access ports to allow occupants to exit from a second port in the event of a collapse on top of the single access.
As such, there exists a need for an easily and inexpensively manufactured storm shelter which can be easily mounted by a user especially occupants of mobile housing that is especially prone to extreme damage from tornados and hurricanes. Such a device should feature an emergency chute for almost instantaneous access to the shelter from the mobile home. Such a device should also feature a plurality of entrances and exits in the highly likely event of a collapse of the mobile home upon one entrance. Such a shelter, when used in combination with mobile housing, should also offer a break away mount communicating between the interior of the shelter and the interior of the mobile home which seals the shelter from the high winds in the event the mobile home is sheared from its moorings.
Applicant""s device is an easily manufactured and installed storm shelter that can be pre manufactured in a number of embodiments to be installed adjacent to a mobile home or conventional housing of wood or other construction. The device in the current best mode would be of an elongated cylindrical shape with hemispherical ends located at each end of the cylinder. The curvature of the elongated cylinder provides exceptional strength against crushing pressure of the surrounding soil as well as potential structures overhead. In areas prone to high water, table anchors could be provided on the exterior of the elongated cylinder section to be attached to cables secured to concrete anchor blocks of a size sufficient to overcome anticipated buoyancy forces or other manner of conventional securement to thereby resist any buoyant forces created by such a combination of soil and water table.
The shelter is formed of fiber reinforced plastic or resin by molding or other conventional process of construction of fiber reinforced structure. Currently, fiberglass reinforced resins which harden to the desired shape of the mold are a common manner to construct such structures. Circumferential reinforcement rings are integrally molded into the cylindrical body to provide additional strength to the cylindrical body portion of the shelter during the manufacturing process.
The shelter device can be manufactured in a number of different sizes to accommodate increasing numbers of occupants during a storm. Of the several embodiments herein disclosed, multiple occupant embodiments would normally be installed horizontally parallel to the center axis of the elongated cylindrical body portion. The single user embodiment would be installed with the center axis of the elongated cylindrical body vertically disposed in a position essentially normal to the plane of the above ground surface.
The cylindrical body will typically be mounted in a properly excavated trench and buried with the top portion of the cylindrical body portion closet to the ground surface, being about two feet below ground level when mounted. The multiple occupant embodiments of the device will feature two access tubes communicating with the interior of the cylindrical body in a sealed relationship at an attachment end, and extending approximately 12 inches above ground level at an entry end opposite the attachment end. The interior of the access tube would be of a diameter sufficient to accommodate anticipated users, generally about 32 inches. The access tubes would be oriented vertical or inclined in relation to the center axis of the cylindrical body portion of the shelter at an angle for best ingress of substantially 45 degrees to the center axis, however, other angles of incline may be used depending on the area available for the device to be mounted and the speed desired for the person entering.
In the one man embodiment of the shelter device a single access tube would be provided which communicates with the interior cavity of the cylindrical body portion at one end and above the ground surface at the distal end. The single access tube would be mounted in the same manner as the double access tubes of the multiple occupant embodiment.
All such access tubes will have a hinged lid covering the entry end. The lid will allow for easy ingress and exit to the shelter device by a simple lifting of the lid to allow users access to the communicating cavity in the cylindrical body portion of the device. The lid in the current best mode features a vent to allow venting of the atmosphere inside the cavity of the cylindrical body with a screen mesh to block access thereto by insects and animals.
Depending on the angle of orientation of the access tube to the center axis of the cylindrical body, the access tubes will feature ladder rungs on the steeper angles and would be configured as an emergency slide on the more obtuse angles such as the 45 degree angle embodiment. To provide for fast entry and double exit from the cavity of the cylindrical body, a first access tube featuring an interior wall surface formed as a slide would provide exceptionally speedy access to the shelter during an emergency. The second access tube would be mounted at an angle substantially normal to the center axis of the cylindrical body and have ladder rungs mounted on the interior wall surface for ingress and egress therethrough.
The solo model for one person might also feature an access tube with a slide or with ladder rungs or both. In the case of the slide, a rope or recessed rungs might also be mounted in the access tube to provide the occupant a manner in which to climb back out of the first access tube.
In the event that water enters the shelter, sufficient sump areas are provided which communicate with the interior cavity of the elongated cylinder to provide drainage.
In the current best mode of the device for use with mobile housing or in some cases through the wall or floor of permanent housing, a break away defined separation point would be placed at the top end of the first access tube using a collared fitting designed to break away or by perforating the tube itself at a designated point to allow a break away of the upper portion during a storm. The defined separation point would be attached to the entry end of the first access tube and would break away from the access tube in the event that the attached home collapses or is sheared from its moorings on the ground. If the separation point is defined by a separation collar it would be especially well suited for attachment to the floor or lower wall surface of mobile housing by providing the ability to allow the collar to break away and not damage the communicating access tube or the shelter itself while allowing the occupant almost instantaneous access to the shelter through a wall or floor surface during an emergency. A second sealing lid would be provided for below the defined separation point in the access tube to allow the users to seal the access tube in case shear forces cause the upper portion of the access tube and lid break to break away. Occupants of mobile housing who are especially endangered by sudden tornados or high windstorms, would thus have immediate access to shelter through a wall or floor surface of the home and would be spared exposure to the high winds seeking other forms of storm shelter that may or may not be provided in trailer parks.
An object of this invention is to provide a prefabricated storm shelter that is easily located adjacent to a home or mobile home providing shelter during dangerous storms.
Another object of this invention is to provide a storm shelter that is easily accessed in the short warning time prior to dangerous storms and easy to exit when the storm passes.
A further object of this invention is the provision an entry point to the shelter that can be communicated through the wall or floors of mobile housing and provide instant access to shelter and break away from the shelter without damaging it should the mobile home be destroyed or sheared from its moorings.
An additional object of this invention is the provision of a design for various sized shelters that can be easily manufactured and installed adjacent to already built homes or newly constructed homes.
A still further object of this invention is the provision of a defined point of separation of the upper portion of the access tube to allow it to be attached to dwellings that might be subject to shear during a storm.
Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.